Protective heating means for third rail electric railways



L. S. WELLS Jan. 14, 1936.

PROTECTIVE HEATING MEANS FOR THIRD RAIL ELECTRIC RAILWAYS Filed April 25, l935- INVENTOR [0991 5 Wzzs ATTORNEY Patented Jan. 14, 1936 UNITED STATES PATENT OFFICE PROTECTIVE HEATING MEANS FOR THIRD RAIL ELECTRIC RAILWAYS Loren Stanford Wells, Great Neck, N. Y.

Application April 25, 1935, Serial No. 18,104

7 Claims. (01. 191-27) This invention relates to protective means for more fully understood by reference to the accomthird rail operated electric railways and is depanying drawing wherein like reference charsigned to afford the greatest protection at the acters are applied to the corresponding parts in minimum of cost, both for installation and operthe several views.

ation, in maintaining the road in operation during In the drawing: periods of severe blizzard or cold weather storm Fig. 1 is a diagrammatic view showing a portion conditions. of third rail electric railway embodying my im- As is well known, the operation to train schedproved protective heating means. ules of third rail, open track railways is seriously Fig. 2 is a detail diagrammatic view illustrating interfered with under blizzard, drifting snow the improved control of the heating circuit. 10 and sleet conditions by reason of the snow and ice Fig. 3 is a partial, vertical sectional view showaccumulations on the third or contact rails. Such ing the location of the heating element for the accumulations interrupt the transmission of. the third or contact rail. power current through the contact shoes and Fig. 4 is a central, longitudinal sectional view r driving motors of the cars, in addition to causing of the improved resistance heating element. destructive arcing at the shoe contacts resulting Fig. 5 is a cross-sectional view thereof.

in hindrance to and at times complete tie-up of In the approved embodiment of my protective operation. Also, as will be appreciated, protecmeans for third rail operated railways as here tion may be afiorded by heating of the third or illustrated, I employ electric resistance units for contact rail as disclosed in my prior Patent No. heating of the third or contact rail. As diagram- 90 1,524,223, dated January 27, 1925, but the cost of matically shown in Figs. 1 to 3, 7' indicates the H installation and current consumption for heatrunning or track rails of an electrified railway ining, on a system of considerable mileage, is excesstallation having the usual insulated and electrisive if not economically prohibitive, particularly cally energized third or contact rail 0 in spaced as related to the rarity of, its essential use for and parallel relation thereto. maintaining operation. To successfully provide an effective contact rail As an efiective and practical solution of the heating protection as described, without prohibiproblem, I have devised a heating means having tive installation and operating cost, I have proa minimum heating requirement of the contact vided for the concentration of the heating at suitrail and wherein heated lengths of rail are spaced ably spaced areas which in practice is determined 30 with relation to normal contact shoe spacing and as to area or length of heated section with relastandard car lengths in electrically coupled relation to the standards of car contact shoe spacing tion to produce an economic installation but sufiiand in the spacing between the heated areas or cient for maintaining operating conditions durintervals with relation to a normal or operating ing periods of heavy and drifting snows which minimum series coupling of the cars or rolling 3r otherwise might tie up traffic. stock. Accordingly, as here illustrated, provision To further contribute in producing an operais made for the protective heating of the contact tively economic protective means for this purpose rail for areas limited with relation to the spacing there is incorporated with the heating circuits, of the car contact shoes and with the heated areas thermostatic controls for the' heater operation to 01 eng s Spa e h e an Operating re at n to o reduce the heating element current consumption a minimum train length of three cars 1) as shown. to the minimum thereby allowing of extending the In the diagra mat illustration of g. 1 and protection areas for a given amount of current as e p y a practical embodiment of y consumption. There is further employed thereinvention, the track or running rails are indicatwith an improved heater control circuit arrangeed at r, the electrified contact rail at 0 having 5 ment allowing of remote control operation of the pa d p t n or areas thereof p tiv y protective heaters from a centralized control staheated by electrical resistance heating elements h tion permitting of automatic control under qualiwhich are energized from the contact rail and fied supervision. Also for use with my improved connected through fuses 7 to a negative or return protective means, I have designed an improved circuit wire 2 and grounding connection 3 having 50 resistance heating element of simplified construoa balanced or compensatinggroundconnection4to tion and which offers important advantages in the track rails. The connection 3 as shown is proinstallations for this purpose. vided with a fuse f and a circuit breaker or con- The foregoing and other important features trol switch s for closing of the circuit through a 5 and advantages of the present invention will be multiple of the heating units as employed with the circuit. In the train of three cars 1; shown, each car is provided with the usual contact shoes 5--5 having a standard distance between the shoes of a car of forty-three feet seven inches center to center spacing with, as will be understood, power bus line electric coupling between the cars whereby proper contact of any one shoe of the train with the contact rail will energize the driving motors of all cars. With a minimum train length for severe weather operation, as thus established, I space the heated contact rail areas with relation thereto toobtain a maximum spacing of the heated areas while providing at all times for shoe contact with a heated rail area. This spacing is substantially a distance slightly less than the distance between the forward shoe of the first car and the rearward shoe of the last car electrically connected by bus line therewith thereby insuring a closed operating circuit at all times. These spaced protected areas or heated lengths of the contact rail may desirably extend from a station location a distance suflicient in advance thereof to allow of obtaining requisite momentum of the train to carry through to the next protected section or area similarly heated. The heaters h employed are of the type comprising an electric resistance heating coil within and insulated from a suitable tubular casing, the heating units being secured in engagement with the contact rail beneath the head portion thereof so that the heat therefrom is conducted directly to the rail. The energizing current is taken from the charged contact rail and at each heated area or length of the contact rail, as here shown, two resistance heating units are employed each having a length of about one-half the distance of the contact shoe spacing so as to give a total length heated area substantially equal to the employed car shoe spacing. In the installation as shown each resistance unit has a length of twenty-two and a half feet giving a protected area greater than the total length of forty-five feet by reason of the extended heat conduction.

To control the operation of the heater circuits, provision is made for remote control from a central point as shown in Fig. 2 comprising a control circuit 6 to coil l of a solenoid operating circuit breaker switch 8, the coil having a ground connection 8 to a track rail r. The control circuit 6, l, 8 is closed from the contact rail by a master switch S operated by a manually closed circuit it having operating coil II for the switch 8.

For special or emergency use in the event of in terruption to the control circuit, a shunting cir cuit is provided by the connections 2e-21 having a manually operated switch 28 which allows of closing'the heater circuit independent of the controlling circuit.

To eiiect a further substantial economy in current consumption there is associated with each circuit controlling the heaters of a given location a thermostatic control switch operative automati cally to open the heating circuit when the con tact rail attains a predetermined maximum heat-- ed condition and to again close the circuit responsive to drop in temperature. This is diagrammatically shown in Fig. 2 wherein it indicates a suitable thermostat or thermal switch ir: series with connection 8 and positioned to be influenced by the heat of the contact rail and 0p erative at low temperatures to close the circuit from the contact rail, through connections 6, i. 8 to the track rail. Accordingly, in operation, opening of the thermostat switch t responsive to high temperature, will open the control circuit 6, 1, 8 thereby releasing the circuit breaker switch to open under the normal action of its spring as customarily employed. Cooling of the contact rail will again allow the control circuit to function to close the circuit breakers and heater circuit thereby automatically effecting a substan tial economy in current consumption while maintaining effective heating.

A shunting connection having switch 33 is provided to allow of cutting out of the thermal switch control which may be desired under very severe weather conditions. This switch 33, when closed, short circuits the thermal control and is operated by. a coil 3i in remote control circuit 32 as indicated. While the remote control circuits it and 32 are shown of the three wire type, it will be understood that the coils H and Si may be in a single circuit when the well known type of selective relay switch and supervising control circuit is employed.

As illustrated in Figs. 4 and 5, I have designed an improved electric resistance heating unit of simple, durable and economic construction particularly adapted for the present use. The heater unit comprises a tubular metal casing l2 having its ends closed by the threaded caps iB-Hi and having positioned centrally and longitudinally extending thereof a resistance heating conductor or coil it having fitted thereon insulator collars or beads l6 insulating and spacing the coil from the casing. One end of the heater coil 55 is secured by terminal screw l? to the cap 53 and the opposite end is secured to a terminal rod is having threaded connection to central conductor terminal is of spark plug type terminal member 28 having clamping nut 2i for the negative lead connection 22. The latter, or negative terminal portion of the heating unit is desirably angularly bent as shown to be offset from the contact rail when assembled therewith. The casing and its opposite cap end portion is secured to the charged contact rail in direct engagement therewith whereby the casing member is in effect the positive electric terminal and eliminates the use of other or special terminal connections with resulting economy and simplification. Fitted upon the rod 5 8 is a coil spring 24 interposed between insulator beads 6 to maintain them in close contact and abutting relation.

While there is shown and described an approved embodiment of the features of my invention, it will be understood that varied modifications may be made therein to meet specific requirements without departing from the invention as defined in the appended claims.

Having described my invention, I claim:

1. A protective heating means for third rail electric railways comprising in combination with the track rails and contact rail parallel thereto, rolling stock adapted to be operated thereover having a plurality of contact shoes spaced substantial distances apart, heaters positioned for heating of the contact rail at spaced areas, each area in length substantially equal to said contact shoe spacing and having the heated areas spaced relative to a determined minimum length of rolling stock to be operatively spanned thereby.

2. A protective heating means for third rail electric railways comprising in combination with the track rails and contact rail parallel thereto, rolling stock adapted to be operated thereover having a plurality of contact shoes spaced subequal to said contact shoe spacing and with the heated areas spaced relative to a determined minimum train length to be operatively spanned thereby and a circuit common to a multiple of the heated areas and connected for energizing the heaters thereof.

3. A protective heating means for third rail electric railways comprising in combination with the track rails and contact rail parallel thereto, rolling stock adapted to be operated thereover having a plurality of contact shoes spaced substantial distances apart, resistance heating units I positioned for heating of the contact rail at spaced areas, each area in length substantially equal to said contact shoe spacing and with the heated areas spaced relative to a determined train length to be operatively spanned thereby, an energizing circuit for the heaters and a thermal responsive switch connected automatically to open and close the heater circuit responsive to temperature changes.

4. A protective heating means for third rail electric railways comprising in combination with the track rails and contact rail parallel thereto, rolling stock adapted to be operated thereover having a plurality of contact shoes spaced substantial distances apart, resistance heating units positioned for heating of the contact rail at spaced areas, each area in length substantially equal to said contact shoe spacing and with the heated areas spaced relative to a determined minimum train length to be operatively spanned thereby, a negative conductor common to a multiple of the heater areas and connected for closing a circuit through the heaters thereof, a control switch associated with said conductor and a control circuit for remote control operation of said switch.

5. A protective heating means for third rail electric railways comprising in combination with the track rails and contact rail parallel thereto, rolling stock adapted to: be operated thereover having a plurality of contact shoes spaced substantial distances apart, resistance heating units positioned for heating of the contact rail at spaced areas, each area in length substantially equal to said contact shoe spacing and with the heated areas spaced relative to a determined minimum train length to be operatively spanned thereby, a circuit connection common to a multiple of the heated areas and connected for energizing the heaters thereof, a control switch in said connection, a control circuit for remote control of said switch and a thermal responsive switch positioned to be influenced by the heat of the contact rail and connected automatically to eifect opening and closing of the heater circuit responsive to temperature changes.

6. A protective heating means for third rail electric railways comprising in combination with the track rails and contact rail parallel thereto, rolling stock adapted to be operated thereover having a plurality of contact shoes spaced substantial distances apart, resistance heating units positioned for heating of the contact rail at spaced areas, each area in length substantially equal to said contact shoe spacing and with the heated areas spaced relative toa determined minimum length of rolling stock to be operatively spanned thereby, a circuit connection common to a multiple of the heated areas and connected for energizing the heaters thereof, a control switch in said connection, a control circuit for remote control of said switch, a thermal responsive switch positioned to be influenced by the heat of the contact rail and connected automatically to effect opening and closing of the heater circuit responsive to temperature changes and a shunt circuit having a switch adapted to close the heating circuit independent of the control circuit operation.

7. A protective heating means for third rail electric railways comprising in combination with the track rails and contact rail parallel thereto, rolling stock adapted to be operated thereover having a plurality of contact shoes spaced substantial distances apart, resistance heating units positioned for heating of the contact rail at spaced areas, each area in length substantially equal to said contact shoe spacing and with the heated areas spaced relative to a determined train length to be operatively spanned thereby, an energizing circuit for the heaters and a thermal responsive switch positioned to be influenced by the heat of the contact rail and connected automatically to open and close the heater circuit responsive to temperature changes and a switch in the thermal switch circuit substantially as described.

LOREN STANFORD WELLS. 

